764 



for pathological purposes, and by it my own results were obtained; 

 unfortunately they are based upon 55 only of my own 100 cases. In 

 these 55 cases very accurate measurements were made in millimetres 

 upon the base, centre and apex of the appendix and give the follow- 

 ing results: 



The average diameter of the appendix is 6 mm at the base and 

 centre and 5 mm at the apex. These figures exactly coincide with 

 Bryant, so that 6 mm may be accepted as the normal average dia- 

 meter of the human vermiform appendix. Henceforward the "goose 

 quiir' similes of size should be replaced by accurate figures. 



The relations of the diameter of the appendix to sex were in my 

 series of cases as follows: 



1. Thirty males, average diameter 6 mm. 



2. Twenty five females, average diameter 5 mm. 



The relations of diameter to age are shown in the annexed table : 



Table III. Relations ofDiameter of Appendix to Age. 

 based upon 55 cases of the Author's Anatomical Series. 



1. Below the age of 10 years 



2. Between 20 and 30 years 



3. Between 30 and 40 years 



4. Between 40 and 50 years 



5. Between 50 and 60 years 



6. Between 60 and 70 years 



7. Between 70 and 80 years 



This table again illustrates the fact that the appendix attains its 

 greatest size during adult and middle age as opposed to the two 

 extremes of life, 



3) Gerlach's Valve. This is a valve which, as its name implies 

 was first described by Gerlach (12), writing in 1847, he says "it is 

 a semilunar fold of mucous membrane guarding the internal appendico- 

 caecal orifice". The importance of this valve is rather pathological 

 than anatomical, for interest is chiefly centred in it on account of the 

 possibility of its causing retention within the lumen of the appendix 

 of the normal appendicular secretion and so producing calculi. 



The presence of the valve does not seem to have been doubted 

 until recently. In 1892, Clado distinctly asserts that he has never 

 found the valve although he has examined a very large number of 

 cases. Kelynack and Fowler agree in the main with Clado, in at 

 all events, doubting its existence. Struthers regards it as "not a 

 valve proper, not a pouch within the orifice resisting reflux like a 

 valve in a vein but merely one of those crescentic edges or folds that 



